Perry Mason: The Case of the Lethal Lesson (1989)

Ken Malansky is a law student attending a class being taught by Perry Mason. When a friend tells him that his girlfriend was assaulted by a fellow student, Ken rushes to the university's mock courtroom to confront him and finds him dead. The murder weapon was Ken's own knife. Perry is reluctant to take on his case, especially since the victim was the son of a close friend.